Explore PHP 8.4 native HTML 5 parser vs html5-php

Problem/Motivation

There's feature freeze of PHP 8.4 coming but new HTML5 classes already available (in alpha releases) and core nww using masterminds/html5 library after 🌱 [Meta] PHP DOM (libxml2) misinterprets HTML5 Active

Steps to reproduce

- new parser and classes implemented in https://wiki.php.net/rfc/domdocument_html5_parser (WHATWG DOM spec added)
- new API is opt-in https://wiki.php.net/rfc/opt_in_dom_spec_compliance
- CSS selectors and more https://wiki.php.net/rfc/dom_additions_84

Proposed resolution

Explore effect of replacement of html5-php library with native implementation from PHP 8.2 and prepare core to get rid off PHP-library in favour of native dom extension (which is required already)

Remaining tasks

- replace create/load methods with new classes and try fix tests
- compare replacement of CSS-selectors library with native implementation

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet